I'd say on signage probably German and French at minimum (even if just small print) with Pictograms/Icons too where appropriate...
Maybe like
Platform
Voie / Gleis
Yeah that's the kind of thing I was thinking of and it wouldn't be too difficult to implement (well in theory), wouldn't be annoying for the natives and would be a big help (hopefully) to visitors.
If more second language announcements/signage were to be introduced, and at the risk of being a traditionalist, it should IMHO be French.
Can you imagine the reaction of the Daily Mail (or the Daily Express for that matter) to that
